Sewage purification system



F. v. HAMMERLY SEWAGEPURIFICATION SYSTEM Filed Feb. 26, 1929 i I Y i I ll I -i hi i l 5|:

1 l l l i 1 J/ l 1' FRIAZVNIZIA5WEGLV March 7, 1933.

' area occupied by the plant, with a corre- Patented Mar. 7, 1933 UNITEDSTATES PATENT OFFICE ram v. mxumr, or minimum muoam nssxeuoa or ems-am'ro cannon.

n. ABBOTT, or BER-1mm, camomwm, AND oma-muro OI BERKELEY, CALIFORNIAGEORGIA. A. HAHMERLY,

SEWAGE PUBIIICA'I'I O N SYSTEM I Application filed February 28, 1928.Serial No. 342,887.

My invention relates to systems for the biological purification ofsewage, and par-' ticularly to systems in which large volumes of sewagemust be handled. 5 An object of my invention is to provide a systemwhich will expedite the biological purification of sewage.

Another object of my invention is to provide a purification system inwhich the air is equally and thoroughly difi'used through all the sewagereceived, thereby maintain mg a complete and continuous saturation withoxygen of the sewa at all times;

Still another object o my-invention is to provide a sewage purificationsystem in which relatively lar e volumes of sewage may be treated in a pant of relatively small size.

, My invention possesses other objects and valuable features, some ofwhich will be set forth in the following description of my inventionwhich is illustrated in the drawing forming part of the s cification. Itis to be understood that I 0 not limit myself 25 to the showing made bythe said descri tion and drawing, as I may adopt varying orms of myinvention within the scope of' the claims.

Of all methods which have been used chemical or bacterial purificationhas proved to be most effective. The method is not without itsdisadvantages, however, for care must be taken to assure a proper supplyof air to the bacteria if their work is not to be excessively slow. Inmany instances this involves duplicate tank systems, in one of which thebacteria are aerating while the other. This adds to the already verylarge spondingly large increase inlfixed charges. By my invention thebacteria in each tank are constantly reaerated, with a correspondingincrease in plant capacity and decrease in time of treatment. 7 v

In terms of broad inclusion, my invention comprises a tank for receivingthe sewage, together with means for circulating the sewage in the tankand mixing it with con-- .ho per.

for the purification of sewage, that of biopurification process is goingforward in the.

trolled amounts of air. Means are also provided for discharging thepurified liquid, and there is also referably provided means forcollecting and removing at intervals the small amount of solid matter ofsludge which accumulates.

Referring to the drawing: 1

Figure 1 is an axial sectional view of the tank and circulating system;and

Figure 2 is a cross sectional View, taken on the line 22 of Fig. 1, ofthe circulating n more detailed terms, apreferred embodiment of myinvention comprises a tank 6, which may conveniently be of concrete, andwhich has a rounded or basin shaped bottom and approximately verticalwalls. Extending across the top of the tank is a aii of girders 7, 7,upon which the circuatin mechanism is su ported.

Su stantially 'central y of the tankthe girders carry a bracket 8 uponwhich is mounted the vertical shaft motor 9.

Hung from the 'rders beneath the motor bymeans of radia fins or webs 11is a hopper 12, the top of the hopper being materially below the'norm'alliquid level of the tank. An extension 13 of the motor shaft, which issupported by a thrust beari passes axial y thru the hopper, and isournaled in a bearing 16. Immediately below the bearing an impellerscrew 17 is mounted; -The inlet duct 18 of the tank enters the side ofthe hopper above the impeller screw. Below thescrew the hopper joins aVenturi tube 19, into the throat of which leads an air duct 21.

Below the outlet of the Venturi tube a deflector 22 is formed in thebottom ofthe tank for directing the flow arallel with the bottom andminimizin t e formation of eddies at this point. urrounding thedeflector is a sump 23 for collecting solid matter orsludgeprecipitating from the tank. A duct 24 leads from the lowest pointof the sump, which may be pumped out at appropriate intervals by-Nmeansof the centrifugal pump 36, or other'suitable mechanism.

The outl P pe 2 is located near the edge excessive formation 0 of thetank and has ahorizontal intake 38 which skims 011' the purified liquidfrom the to Although it is not essential to the operation of the system,it is desirable to provide a baflle 39, substantially concentric withthe tank, for directing circulation in the tank and regulating theformation of eddies.

In 0 oration the motor driven impeller forces t e sewage in the tankdown thru the hopper, the supportin fins 11 preventing vortices andconsequent cavitation of the screw. Fresh sewa e admitted thru the duct18 comprises about 6 to 7% of the material handled b the screw and b itis thoroughly mixed wit the other liquid: passing thru the throat of theventuri 1n a violently agitated state.

Air is drawn 'thru the duct and is entrained with the sewage at thethroat of the tube, oxygen being dissolved therefrom until saturationobtains. This oxygen and the dissolved organic material are the foodupon which the bacteria are propagated, their life processes fixing theoxygen to the organics to yield an innocuous productw Owing to thethorou h distribution of the active culture thru t e aerated sewage,which gives it an abundance of food in a favorable environment, thebiological purification is carried on under the most favorableconditions.

Circulation from the mouth of the venturi follows the eneral courseindicated by the arrows. A ter leaving the throat of the Venturi, thevelocities drop rapidly, iving time for the oxidizing action of thebacteria. Material in the tank passes thru the hopper on the averageabout sixteen times before it is discharged, each time reaerating thebacteria content, and inoculating the new supply of untreated sewage.The fully urified materials, being almost wholly li uld, gather at therelatively undisturbed e ge of the tank and escape thru the outlet duct37.

It will be realized that the size of a purification plant is directlyproportional to the amount of material to be handled in a given time,multiplied by the length of time it must be stored to permit thebacteria to act. By introducin an ample supply'of oxygen to maintain t ebacteria it is desired to propagate and by insuring the immediate andthorough inoculation of all incoming material, this time is greatlyreduced, with a corresponding decrease in size and expense of plant andan increase in dependability of operation. The cost of powerconsumed'by" my device is more than offset by the reduction of fixedcharges.

I claim:

1. A sewage purification system comprising a tank having a basin-shapedbottom, a hopper disposed adjacent the center of the tank, an inlet ductfeeding the hopper, 0.

mechanically driven impeller for breaking up the sewage particles andfor forcing the circulation of the sewage thru the hopper and againstthe tank bottom, and means for injectin air into the sewage after it haspassed t e impeller.

2. A sewage purification s stem comprising a tank, a hop er dispose insaid tank in the upper part t ereof, arranged to admit sewage from thetank into the hopper, a tube connected with the lower end of the hopper,dlscharging in the bottom part of the tank, and forming, with the hop)er, a passage for sewage from the top portion of the tank to its bottomportion, a sewage inlet duct feeding into the hopper, an im ellerlocated below the level of the sewage 1n the tank and adjacent the lowerend of the hopper for agitating and circulating the sewage downwardlythrough the passage and an air duct for injecting air into the passagebelow the level of sewage in the tank and adjacent the impeller.

3. A sewage purification system comprising a tank, having a basin-shapedbottom, a hopper disposed adjacent the center of the tank and arrangedto admit the sewage from the tank into its upper portion, a Venturi tubeconnected with the outlet of the hopper and discharging adjacent thebottom of the tank, an inlet duct feeding into the hopper, an air ductconnected with the throat of the Venturi tube, and a mechanically drivenimpeller for forcing the circulation of the sewage thru the hopper.

4. A sewage purification system comprising a tank having a basin-shapedbottom, a hopper disposed adjacent the center of the tank and arrangedto admit the sewage from the tank into 1ts upper portion, a Venturi tubeconnected with the outlet of the hop- 7 per and discharging adjacent thebottom of the tank, an inlet duct feeding into the hopper, an air ductconnected with the throat of the Venturi tube, and a mechanically drivenscrew impeller for agitating and circulating the sewage thru the hopper.

5. A sewage purification system comprising a tank having a basin-shapedbottom, a ho per disposed adjacent the center of the tan and arranged toadmit the sewege from the tank into its upper portion, a

enturi tube connected with the outlet of the hopper and dischargingadjacent the bottom of the tank, an inlet duct feedin into the hopper,an air duct connected witi ,..ar throat of the Venturi tube, amechanically driven screw impeller for agitating and circulating thesewage thru the hopper, and means within the hopper for regulating theformation of vortices.

6. A sewage purification system comprising a tank having a basin-shapedbottom, a hopper disposed adjacent the center of the tank and arrangedto admit the sewage from the tank into its upper portion, a Venturi tubeconnected with the outlet of the hopper and discharging adjacent thebottom of the tank, an inlet duct feeding into the hopper, an air ductconnected with the throat of the Venturi tube, a deflector adjacent thedischarge opening of the Venturi tube for directing the circulationtherefrom along the bottom of the tank, and means for forcingcirculation of the sewage thru the hopper and the Venturi tube.

7. A sewage purification system comprising a tank having a basin-shapedbottom, a hopper disposed adjacent the center of the tank and arrangedto admit the sewa e from the tank into its upper portion, a enturi tubeconnected with the outlet of the hopper and discharging adjacent'thebottom of the tank, an inlet duct feeding into the hopper, an air ductconnected with the throat of the Venturi tube, a deflector adjacent thedischarge opening of the Venturi tube for directing the circulationtherefrom along the bottom of the tank, a sump surrounding thedeflector, means for removing material collected by the sump, and meansfor forcing circulation of the sewage thru the hopper and the Venturitube.

8. A sewage purification system comprising a tank, a hopper disposedadjacent the upper part of the tank and arranged to admit the sewagefrom the tank into its upper portion, an inlet duct feeding the ho perwith raw sewage, an impeller positione below the hopper for breaking upthe sewage particles and for forcing circulation of the mixed raw andtank sewage thru the hopper in a downwardly moving stream, and a ductopening into said stream below the imller for introducing air into thestreammg sewage mixture after it has pased the im ller liiiltessimonywhereof, I have hereunto set my an FRED V. HAMMERLY.

